Adhesives. Determination of free monomer content in adhesives based on synthetic polymers

2001 ◽  
1958 ◽  
Vol 31 (1) ◽  
pp. 82-85
Author(s):  
D. Barnard

Abstract The preparation of graft and block interpolymers of natural rubber and synthetic polymers has made it desirable that the number and size of polymer chains attached to rubber be readily determinate. The degradation of unsaturated polymers with tert-butyl hydroperoxide in the presence of osmium tet oxide has been used for the determination of free polystyrene in SBR and carbon black in several elastomers, and has recently been applied to the present problem. The accurate determination of the rubber content of interpolymers by quantitative ozonolysis essentially according to the method of Boer and Kooyman suggested that this might be made the basis of isolation of the attached polymer, the rubber being degraded into fragments of low molecular weight, from which the polymer could be separated by conventional techniques. The method should be applicable to any interpolymer, or mixture, of a polyunsaturated and a saturated polymer and is illustrated with reference to interpolymers of natural rubber (NR)-polymethyl methacrylate (PMM) and NR-polystyrene (PS).


Author(s):  
K. M. Haunton ◽  
D. Vesely

The knowledge of beam spreading is important for determination of spatial accuracy and volume calculation in quantitative X-ray analysis. It is also useful for determination of best conditions for electron beam lithography with high line resolution. The theoretical modelling of beam spreading is difficult as for example the Monte Carlo simulation is very demanding on computer time and many simplifications have to be made. The validity of the theoretical results must therefore be verified experimentally.In this work some new techniques are utilised for evaluation of the spatial distribution of the deposited energy in synthetic polymers, namely the formation of isolated and conjugated double bonds, revealed by staining and by fluorescent microscopy.Thick samples of PVC, PS and PMMA were coated with about 10 nm of carbon and exposed to an electron beam of 75 - 200 keV for different lengths of time. A Hitachi 700H transmission electron microscope (TEM) was operated in the scanning (STEM) mode. Currents of lxl0−9A and 2x10−10A were used. The stationary beam was convergent or parallel.


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